JP2004005926A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive that shortens a time for obtaining an appropriate wobble clock after a seek operation. <P>SOLUTION: This optical disk drive has a mark for clock synchronization and a recordable data part on tracks. The optical disk drive is provided with a clock synchronizing signal reproducing part for extracting a reproduced signal for the mark for clock synchronization from an output of a photoelectric converter, a clock generating part for generating a clock signal of a variable frequency, a phase synchronization control part for controlling the clock generating part so as to synchronize the clock signal with an output of the clock synchronizing signal reproducing part in phase, and a moving device for moving the spot position of a light beam on an optical disk toward a target track. In performing a seek operation that moves the spot position of the light beam on the optical disk toward the target track in the optical disk, a frequency expected in the target track is determined, and the clock generating part is controlled so as to output a clock signal of a frequency of warping from the clock generating part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc device, and more particularly to frequency control of a wobble PLL when recording and reproducing an optical disc having a wobbled track, and to switching of characteristics of a band-pass filter for detecting a wobble signal.
[0002]
[Prior art]
FIG. 1A shows the overall configuration of an optical disk 101 such as a DVD-RAM, and FIG. 1B shows the sector configuration of a certain zone on the optical disk 101.
[0003]
The information surface of an optical disc 101 such as a DVD-RAM is divided into a plurality of zones 1102 and 1103 as shown in FIG. The recording linear density on the innermost track of each zone is designed to be constant on one optical disk irrespective of the position of the zone itself. On the other hand, in each zone, the recording linear density on the track decreases as the position of the track approaches the outer circumference from the inner circumference.
[0004]
As shown in FIG. 1B, each zone 1104 is divided into a plurality of sectors 1105 and 1106. Each sector includes an address portion arranged at the head of the sector and a data portion following the address portion. Have.
[0005]
FIG. 2 is a plan view showing a detailed configuration of tracks on the optical disc 101. In the optical disc 101 shown in FIG. 12, land tracks 1201 and groove tracks 1202 are alternately arranged in the radial direction. On each track, data sections 1203 and 1204 and address sections 1205 and 1206 are arranged at predetermined intervals in the track direction. The address portion is provided at a position shifted from the center of the track by half the track pitch in the disk radial direction so that the address can be read when the light beam follows either the land track or the groove track.
[0006]
The track 1207 in the data portion is wobbling as a clock synchronization mark. The cycle of the wobble is about several hundred times the cycle of the data read clock.
[0007]
When the light beam irradiates the surface of the optical disk with a light beam and follows the track, a wobble signal is detected from light reflected from the optical disk. Since the wobble signal changes in a cycle corresponding to the cycle of the wobble, PLL control can be performed based on the cycle of the wobble signal.
[0008]
FIG. 3 shows a configuration of an optical disk apparatus that can record data on the optical disk 101 having the above-described configuration or reproduce data from the optical disk.
[0009]
According to the illustrated optical disk device, the light beam is emitted from the head unit 102 and converges on the optical disk 101. The light reflected by the optical disc 101 is detected by a photodetector 103 attached to a head unit 102, and the photodetector 103 outputs an electric signal corresponding to the intensity of the received reflected light.
[0010]
At the time of data recording / reproduction, the optical disc apparatus operates such that the convergence point (light beam pot) of the light beam follows the center of the track on the recording surface of the rotating optical disc 101. Specifically, the head unit 102 moves to an appropriate position so that the light beam spot is on a desired track, and the position of a converging lens (not shown) attached to the head unit 102 is determined by the actuator. Fine-tuned.
[0011]
When reproducing data from the optical disc 101, two outputs of the photodetector 103 shown in FIG. 3 are input to a subtractor 105, and a signal is detected from an address of a track from the output of the subtractor 105. Specifically, the photodetector 103 has photodiodes divided into two so as to correspond to the tangential direction of the track, and converts the light received by each photodiode into an electric signal and outputs the electric signal. I do. The output of the subtractor 105 corresponds to the output difference between the two photodiodes, and includes the information corresponding to the wobble of the track followed by the light beam spot and the information of the address portion.
[0012]
Referring to FIG. 4A and FIG. FIG. 4A is a plan view schematically showing the shape of a track, and FIG. 4B shows the waveform of the output (difference signal) of the subtractor 105.
[0013]
The address part detection unit 106 of the optical disk device shown in FIG. 3 detects the address part of the track where the light beam spot is located based on the difference signal shown in FIG.
[0014]
Next, the configuration and operation of the address part detection unit 106 will be described with reference to FIG. FIG. 5 is a diagram showing an internal configuration of the address part detection unit 106. The output (difference signal) of the subtractor 105 is input to the low-pass filter 1401 in FIG. The low-pass filter 1401 is a filter that blocks a signal having a high frequency higher than the RF component band (for example, 1.2 to 4.5 MHz). The output of the low-pass filter 1401 has the waveform shown in FIG. Although not shown in FIG. 4B, even if a high frequency component exists in the difference signal, it is cut by the low-pass filter 1401.
[0015]
The output of the low-pass filter 1401 is compared with two reference levels, and the information of the address part is determined depending on whether the output is higher or lower than the reference level. Specifically, the comparator 1402 in FIG. 5 detects whether the output of the low-pass filter 1401 is equal to or higher than “address part detection level 1”, and determines whether the output is equal to or higher than “address part detection level 2”. Is detected by the comparator 1403. The magnitudes of the “address part detection level 1” and the “address part detection level 2” are set in advance so that signals from the address part can be identified from the wobble signal, as shown by the broken lines in FIG. .
[0016]
The OR operation element 1404 performs an OR operation on the output of the comparator 1402 and the output of the comparator 1403, and outputs an address part detection signal shown in FIG.
[0017]
Gate signal generation section 113 receives an output signal from address section detection section 106 and outputs the signal to selector 110 and data PLL circuit 112. The selector 110 receiving the signal passes the output of the selector 109, which is an address reproduction signal, and inputs the signal to the equalizer unit 111. The equalizer unit 111 has a function of amplifying a signal in a designated frequency band, limiting transmission of a signal in another band, and binarizing the signal, and outputs a reproduced RF signal. The reproduced RF signal is input to the data PLL circuit 112, and the data PLL circuit 112 outputs a data read clock synchronized with the reproduced RF signal. The data read clock is a reference when reproducing a signal.
[0018]
FIG. 6 is a diagram showing an internal configuration of the data PLL circuit 112. The period measuring device 1707 measures the period of the wobble signal. This measured value is amplified by the amplifier 1709 and input to the comparator 1710. A signal generated by dividing the frequency of the data read clock by the frequency divider 1705 is input to the period measuring device 1708, and the period is measured. The period measured by the period measuring device 1707 and the period measured by the period measuring device 1708 are compared by the comparator 1710. The comparator 1710 outputs a control signal based on the comparison result. This control signal passes through the selector 1706 switched by the system controller 1317 and the phase compensator 1703 and is input to the variable oscillator 1704. The variable oscillator 1704 controls the oscillation frequency so that the period of the data read clock has a constant ratio with respect to the period of the wobble signal.
[0019]
On the other hand, when reproducing addresses and data, the system controller 1317 switches the selector 1706. In this case, the output of the phase comparator 1701 is input to the variable oscillator 1704 through the switch 1702, the selector 1706, and the phase compensator 1703. The phase comparator 1701 compares the data read clock frequency-divided by the frequency divider 1705 with the phase of the reproduced RF signal. The variable oscillator 1704 controls the oscillation frequency so that the data read clock is synchronized with the reproduced RF signal.
[0020]
A logical sum of an address part gate signal indicating an address part and a data part gate signal indicating a data part in a sector for reproducing data is calculated by a logical sum operator 1711, and an output of the logical sum operator 1711 is sent to the switch 1702. Thus, the data PLL circuit 112 performs the phase comparison operation only on the address part and the data part in the sector for reproducing data.
[0021]
FIG. 3 is referred to again.
[0022]
The address read unit 116 reproduces an address from the data read clock and the reproduced RF signal based on the output of the gate signal generation unit 113.
[0023]
The selector 109 selects whether to reproduce the address with the output of the subtractor 105 or the output of the adder 104 according to the signal sent from the system controller 1317 according to the optical disk to be reproduced.
[0024]
Next, reference is made to FIG. FIG. 7 is a diagram showing the internal configuration of the wobble detection unit 1307. The wobble detection unit 1307 extracts a wobble signal 1207 of the data units 1203 and 1204 in the track shown in FIG. 2 using a band-pass filter based on the output of the subtractor 105, and generates a wobble detection signal. The wobble detection signal has, for example, a waveform as shown in FIG. The wobble detection unit 1307 binarizes the wobble detection signal extracted using the band-pass filter with a comparator, and outputs a wobble signal. The wobble signal has a waveform shown in FIG.
[0025]
The wobble PLL circuit 1308 in the optical disk device of FIG. 3 performs PLL control based on the wobble signal. FIG. 8 is a diagram showing the internal configuration of the wobble PLL circuit 1308. In FIG. 8, a frequency control unit is configured by a period measuring device 207, a period measuring device 208, an amplifier 209, and a comparator 210.
[0026]
First, the period of the wobble signal is measured by the period measuring device 207, and the measured value is amplified by the amplifier 209, and the measured value of the frequency of the divided wobble clock is measured by the period measuring device 208. A comparison is made at 210 and a control signal is output. This control signal passes through a selector 1806 switched by a system controller 1317 and a phase compensator 203, and is input to a variable oscillator 204 which is a clock generating means, so that the ratio of the period of the wobble clock to the period of the wobble signal becomes substantially constant. Controlled.
[0027]
When this ratio becomes substantially constant, the system controller 1317 switches the selector 1806 and compares the phase of the wobble clock divided by the frequency divider 205 with the phase of the wobble signal by the phase comparator 201 as phase synchronization control means. The output of the phase comparator 201 passes through the switch 202 and the phase compensator 203, is input to the variable oscillator 204, and is controlled so that the wobble clock is synchronized with the wobble signal. Also, since the wobble signal is only in the data section, if the address section is detected by the output of the address section detection section 106 while controlling the wobble clock to be synchronized with the wobble signal, the switch 202 is turned off in conjunction with this. Then, the phase comparison operation is temporarily stopped.
[0028]
The gate signal generating unit 113 outputs an address part gate signal indicating an address part to the selector 110 according to a command from the system controller 1317. The system controller 1317 generates an address part gate signal based on the wobble clock when the address can be read, and generates an address part gate signal based on the output signal of the address part detection part when the address cannot be read. A signal is sent to the signal generator 113. When reading data from the data section or recording data in the data section, the system controller 1317 sends a signal to the gate signal generation section 113, and the gate signal generation section 113 transmits a data section gate signal indicating the data section. Output.
[0029]
When recording data, the recording control unit 118 sends recording data sent from the system controller to the head unit 102 in synchronization with the wobble clock based on the data part gate signal, and records the data on the optical disc 101.
[0030]
Such an optical disk device is described in, for example, Patent Documents 1 and 2.
[0031]
[Patent Document 1]
JP 05-225580 A
[Patent Document 1]
JP 2000-10083 A
[0032]
[Problems to be solved by the invention]
According to the above-described conventional optical disk device, a wobble signal is detected from an electric signal (reproduction signal) output from the photodetector 103 during a period in which tracking control is not performed, such as during a seek operation performed by moving the head unit 102. I can't. For this reason, in the conventional optical disk device, the control of the wobble PLL is not appropriately performed during such a period, and a clock having a frequency different from the original frequency is generated.
[0033]
According to the conventional optical disk device, the wobble PLL is operated by the wobble signal detected after the seek operation, so that it takes time to pull in the desired frequency, and it takes time from the end of the seek to the time the wobble PLL operates properly. There's a problem.
[0034]
Hereinafter, the above problem will be described in more detail with reference to FIG. FIG. 9 shows the tracking error signal, the number of rotations of the disk motor, and the wobble clock when the tracking operation changes from the tracking operation to the seek operation and back again.
[0035]
When performing a ZCLV (Zone Constant Linear Velocity) operation, the optimal rotation speed of the disk motor and the cycle of the wobble clock differ depending on which track of the optical disk the optical beam spot is located on. In FIG. 9, “N1” is the optimum number of revolutions of the disk motor corresponding to the position of the light beam spot before the start of the seek, and “N2” is the optimum number of rotations of the disk motor corresponding to the position of the light beam spot after the seek. The number of rotations is shown. The example shown in FIG. 9 shows a case where the position of the light beam spot has moved from the inner circumference to the outer circumference of the disk due to the seek operation.
[0036]
According to the conventional optical disk device, the tracking control is turned off before the seek operation is started, and the tracking control is turned off during the seek operation. For this reason, the wobble signal cannot be detected, and the frequency of the wobble clock is disturbed as shown in FIG.
[0037]
Since the tracking operation is turned on from the end time t1 of the seek operation, the frequency of the wobble clock disturbed during the seek operation changes to an appropriate value after the time t1, and the appropriate wobble clock frequency is changed at the time t2. To reach.
[0038]
In FIG. 9, a broken line 1901 indicates an optimum wobble clock frequency in a new track (target track) after the end of the seek operation. Such a wobble clock frequency changes depending on the rotation speed of the disk motor. During the seek operation, since the rotation speed of the disk motor changes as shown in FIG. 9, a broken line 1901 indicates an appropriate wobble clock (at the target track) which should change in response to such a change in the rotation speed. The frequency is shown.
[0039]
When the seek operation ends and the light beam spot reaches the target track and the tracking operation starts, the rotation speed of the disk motor has not reached "N2" as shown in FIG. The point in time when the rotation speed of the disk motor reaches "N2" is delayed according to the response speed of the motor. Therefore, even when the adjustment of the wobble clock frequency is started along with the start of the tracking operation, it is at time t2 that the wobble clock frequency matches the magnitude indicated by the broken line 1901. This is because it takes a time “t2−t1” until the wobble PLL is locked. Therefore, even if the seek speed is high, it takes time to obtain an appropriate wobble clock.
[0040]
Further, in the conventional optical disk device, since the frequency characteristic of the band-pass filter for detecting the wobble signal is fixed, when the reproduction speed is changed or when CAV (Constant Angular Velocity) reproduction is performed, the reproduction is not performed. There is also a problem that the frequency of the wobble signal falls outside the pass band of the band-pass filter, and the wobble signal cannot be detected.
[0041]
The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide an optical disk device in which the time required to obtain an appropriate wobble clock after a seek operation is reduced.
[0042]
It is another object of the present invention to provide an optical disk device capable of preventing the frequency of a reproduced wobble signal from deviating from the pass band of a band-pass filter.
[0043]
[Means for Solving the Problems]
An optical disk device according to the present invention converges and irradiates a light beam onto an optical disk having a clock synchronization mark and a recordable data portion on a track to read information recorded on the optical disk or write information to the optical disk. An optical disk device, comprising: a motor for rotating the optical disk; a photoelectric converter that converts reflected light or transmitted light from the optical disk into an electric signal and outputs the electric signal; and an electric device that outputs the electric signal. A clock synchronization signal reproducing unit for extracting and outputting a reproduction signal of the clock synchronization mark from a signal; a clock generation unit for generating a clock signal of a variable frequency; A phase synchronization control unit that controls the clock generation unit so as to synchronize, A moving device for moving a spot position of the light beam to a target track in the optical disc, and a seek operation for moving the spot position of the light beam on the optical disc to a target track in the optical disc. When performing, the expected frequency of the target track is determined, and the clock generation unit is controlled so that the clock signal of the frequency is output from the clock generation unit.
[0044]
In a preferred embodiment, a period in which a clock signal having an expected frequency in the target track is output from the clock generation unit starts in accordance with a timing of starting movement of a spot position of the light beam for the seek operation, The process ends before the movement of the spot position of the light beam ends.
[0045]
In a preferred embodiment, in the optical disc, an information area is concentrically divided into a plurality of zones, and in each of the plurality of zones, the recording linear density becomes lower toward an outer track, and Information is recorded such that the recording linear density of the innermost track is substantially constant on the optical disk, and the clock synchronization mark and the recordable data portion are provided in each zone.
[0046]
In a preferred embodiment, the track of the optical disc has a wobble structure that periodically shifts in a radial direction, and the wobble structure functions as the clock synchronization mark.
[0047]
In a preferred embodiment, the wobble structure of the track on the optical disc also functions as a portion for recording address information.
[0048]
In a preferred embodiment, a rotation speed detection for detecting a rotation speed of the optical disc Department When the rotation speed of the optical disc is changed in accordance with the spot position of the light beam on the optical disc, the frequency of the clock signal is changed to the rotation speed of the detected optical disc and the belonging of the target track. The clock generator is controlled so that the frequency is determined according to the target rotation speed in the zone.
[0049]
In a preferred embodiment, a rotation speed control unit for keeping the rotation speed of the optical disk substantially constant is provided, and the clock generation unit is controlled so that the frequency of the clock signal becomes a target frequency in the target track.
[0050]
Another optical disk device according to the present invention is an optical disk that converges and irradiates a light beam onto an optical disk having a clock synchronization mark and a recordable data portion to read information recorded on the optical disk or write information to the optical disk. A device for rotating the optical disk, a photoelectric converter that converts reflected light or transmitted light from the optical disk into an electric signal, and outputs the electric signal, and the electric signal output from the photoelectric converter. A band-pass filter that extracts a signal of a specific frequency band from the frequency band is variable, and a clock synchronization signal reproducing unit that extracts and outputs a reproduction signal of the clock synchronization mark from an output of the band-pass filter. A clock generator for generating a clock signal of a variable frequency; A phase synchronization control unit that controls the clock generation unit so as to be phase-synchronized with the output of the signal reproduction unit; a linear velocity detection unit that detects the linear velocity of the optical disc; and controls the frequency band that the band-pass filter extracts. And a frequency band control unit that controls a frequency band to be extracted by the band-pass filter based on an output of the linear velocity detection unit.
[0051]
In a preferred embodiment, there is provided an optical disk device which converges and irradiates a light beam onto an optical disk having a clock synchronization mark and a recordable data portion to read information recorded on the optical disk or write information to the optical disk. A motor for rotating the optical disc;
Still another optical disk device according to the present invention converts a reflected light or a transmitted light from the optical disk into an electric signal, and outputs a specific electric signal from the electric signal output from the photoelectric converter. A band-pass filter that extracts a signal of a frequency band and the frequency band is variable; a clock synchronization signal frequency detection unit that detects a reproduction signal frequency of the clock synchronization mark from an output of the band-pass filter; A read clock generator for generating a read clock signal; and a frequency controller for controlling the read clock generator so that the frequency of the read clock signal has a fixed ratio with the frequency of the output of the clock synchronization signal frequency detector. The lead clock signal so that the read clock signal is phase-synchronized with the electric signal output from the photoelectric converter. A phase synchronization controller for controlling a clock generator, a linear velocity detector for detecting a linear velocity of the optical disc, and frequency band control means for controlling the frequency band to be extracted by the band-pass filter; The control means controls a frequency band to be extracted by the band-pass filter based on an output of the linear velocity detecting unit.
[0052]
In a preferred embodiment, a moving device for moving the light beam toward a target track in the optical disk, and a rotation speed detection for detecting a rotation speed of the optical disk changed according to a position of the light beam A linear velocity detector for detecting a linear velocity based on the detected rotational velocity of the optical disc and a frequency determined according to a target rotational velocity in a zone to which the target track belongs.
[0053]
In a preferred embodiment, the apparatus further comprises a moving device for moving the light beam toward a target track in the optical disc, and a rotation speed control unit for keeping a rotation speed of the optical disc substantially constant, wherein the linear velocity detection is performed. The device detects a linear velocity based on a zone to which the target track belongs.
[0054]
In a preferred embodiment, in the optical disc, an information area is concentrically divided into a plurality of zones, and in each of the plurality of zones, the recording linear density becomes lower toward an outer track, and Information is recorded such that the recording linear density of the innermost track is substantially constant on the optical disc, and the clock synchronization mark and the recordable data portion are provided in each zone.
[0055]
In a preferred embodiment, an address section is provided on a track of the optical disc, and an address section detection section that detects the address section based on the electric signal output by the photoelectric converter; and an address section detection section. A sector reproduction time measuring unit for measuring a time interval at which the light beam passes through the sector based on the output of the sector speed detector, wherein the linear velocity detector detects the linear velocity based on the output of the sector reproduction time measuring means. .
[0056]
In a preferred embodiment, the track of the optical disc has a wobble structure that periodically shifts in a radial direction, and the wobble structure functions as the clock synchronization mark.
[0057]
In a preferred embodiment, the wobble structure of the track on the optical disc also functions as a portion for recording address information.
[0058]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0059]
(Embodiment 1)
First, with reference to FIG. 10, a description will be given of the number of rotations of a disk motor when reproducing data from an optical disk by the ZCLV method. In this case, in order to keep the reproduction speed constant during the reproduction of the optical disk, the rotational speed of the motor is changed stepwise according to the radial position of the zone to which the track on which the data to be reproduced belongs belongs.
[0060]
In the graph of FIG. 10, the vertical axis indicates the number of rotations of the motor, and the horizontal axis indicates the position of the reproduction track (the distance from the center of the disk). In the example of FIG. 10, the motor rotation speed differs for each zone, and the motor rotation speed is set lower in the zone outside the disk.
[0061]
As shown in FIG. 10, the rotation speed of the disk motor differs depending on which track of the optical disk the optical beam spot is located on (which zone the track belongs to). When an appropriate motor rotation speed cannot be obtained in each zone, it is necessary to appropriately adjust the generation of the wobble clock according to the motor rotation speed.
[0062]
Next, reference is made to FIG. This figure corresponds to FIG. That is, FIG. 11 shows the tracking error signal, the number of rotations of the disk motor, and the frequency of the wobble clock when the tracking operation is performed, the seek operation is performed, and then the tracking operation returns.
[0063]
In FIG. 11, “N1” is the optimum rotation speed of the disk motor corresponding to the position of the light beam spot before the start of the seek, and “N2” is the optimum number of rotations of the light beam spot after the seek (the target track). Motor rotation speed. The example shown in FIG. 11 shows a case where the position of the light beam spot has moved from the inner peripheral side to the outer peripheral side of the disk due to the seek operation. Note that a broken line 601 in FIG. 11 indicates an optimal frequency characteristic of the wobble clock corresponding to a change in the rotation speed of the disk motor when the head unit moves.
[0064]
In the present embodiment, first, the tracking control is turned off before starting the seek operation. After the seek operation is started, a frequency expected in the target track is determined, and a clock signal having the frequency is generated. Therefore, during the seek operation, the wobble clock frequency has a value indicated by a broken line 601.
[0065]
When the light beam spot is moved from the position x1 to the position x2 on the optical disk, for example, it is necessary to reduce the number of rotations of the motor from N1 to N2. Is moved at a high speed, the motor rotation speed does not reach N2 when the head unit moves to the target position, and shows a value larger than N2. This remarkably occurs when the response of the disk motor is slow.
[0066]
In such a case, the linear velocity of the light beam spot at the seek operation time t1 differs from the specified velocity. Therefore, the wobble reproduction frequency immediately after the head unit is moved to the target position is different from the predetermined reproduction frequency corresponding to the target position.
[0067]
In the present embodiment, in order to solve such a problem, the system controller determines the ratio N / N2 of the rotation speed N2 of the movement destination of the light beam spot by the seek operation and the current rotation speed N to the target value of the wobble clock frequency. Is set, and a wobble clock having a frequency corresponding to the target value is generated. Note that a broken line 601 shown in FIG. 11 indicates a value corresponding to such a correction target value. As the actual rotational speed N of the motor approaches N2, the ratio N / N2 approaches 1.
[0068]
Hereinafter, the optical disc device of the present embodiment will be described in more detail with reference to FIG. 12, the same components as those shown in the drawings of the related art are denoted by the same reference numerals, and the detailed description thereof will be omitted.
[0069]
The optical disc apparatus according to the present embodiment reads an information recorded on an optical disc by converging and irradiating a light beam on an optical disc having a clock synchronization mark and a recordable data portion on a track, or writes information on the optical disc. Device. A typical example of such an optical disk is a DVD-RAM.
[0070]
The optical disc device includes a disc motor (not shown) for rotating the optical disc 101, a photodetector 103 for converting reflected light from the optical disc 101 into an electric signal and outputting an electric signal according to the intensity of the reflected light, and an optical disc 101. A moving device 123 for moving the spot position of the light beam above toward a target track in the optical disc.
[0071]
The rotation speed of the disk motor is controlled so that data can be recorded / reproduced at a predetermined recording / reproducing speed. During the recording / reproducing operation, focus control is performed so that the light beam spot (convergence point) is located on the information recording surface of the optical disc 101, and tracking control is also performed so that the light beam spot follows a predetermined track. Done.
[0072]
Tracking control is performed by generating a tracking error signal by a known method, driving an actuator in the head unit 102 so as to reduce the amplitude of the tracking error signal, and adjusting the position of a converging lens (not shown). Is Note that the tracking error signal is a signal corresponding to the positional deviation between the convergence point of the light beam and the track, and the TE generation unit 119 generates the tracking error signal based on the output of the subtractor 105. The tracking error signal is supplied to the drive circuit 122 via the switch 121 after its phase is compensated by the phase compensator 120. The drive circuit 122 controls the position of a convergent lens (not shown) attached to the head unit 102 with high accuracy. Thus, the tracking control is performed so that the convergence point of the light beam is located on the track. However, when performing the seek operation, the switch 121 is opened for the purpose of turning off the tracking control.
[0073]
The optical disk device includes a clock synchronization signal reproducing unit (wobble detection unit 107) that extracts and outputs a reproduction signal of a clock synchronization mark from an electric signal output by the photodetector 103, and outputs the output of the wobble detection unit 107 to a wobble PLL. The signal is sent to the circuit 108. As will be described in detail later, the wobble PLL circuit 108 includes a clock generation unit that generates a clock signal of a variable frequency, and a phase control unit that controls the clock generation unit so that the clock signal is phase-synchronized with the output of the clock synchronization signal reproduction unit. A synchronization control unit.
[0074]
According to the optical disc device of the present embodiment, when performing a seek operation for moving the position of the light beam spot on the optical disc 101 toward the target track in the optical disc 101, the expected frequency of the target track is determined, The clock generator can be controlled so that the clock signal is output from the clock generator.
[0075]
Note that among the components shown in FIG. 12, the selectors 109 and 110, the equalizer 111, the data PLL 112, the gate signal generator 113, the address read unit 116, and the like are basically the same as the conventional one shown in FIG. . Therefore, hereinafter, the optical disk device of the present embodiment will be described focusing on the configuration and operation of the wobble detection unit 107, the wobble PLL circuit 108, and the like.
[0076]
First, the wobble PLL circuit 108 will be described.
[0077]
Please refer to FIG. FIG. 13 is a diagram corresponding to FIG. 8 and shows the internal configuration of the wobble PLL circuit 108.
[0078]
The wobble PLL circuit 108 according to the present embodiment includes a comparator 211 to which a target wobble clock frequency is input. The target wobble clock frequency (target value) is determined based on the target reproduction speed, the rotation speed of the disk motor, and the target rotation speed at the seek destination, and is input to the comparator 211.
[0079]
Before the seek operation is started, the selector 206 is controlled so that the output of the phase comparator 201 passes therethrough. Therefore, the wobble clock is controlled so that its frequency becomes a constant ratio with the wobble signal frequency. . The generation of the wobble clock at this stage is the same as that in the conventional optical disk device.
[0080]
At this stage, the operation of the data PLL circuit 112 shown in FIG. 12 is controlled so that the frequency of the data read clock has a fixed ratio to the wobble signal frequency.
[0081]
When the movement of the head unit 102 is started from this state, the system controller 117 turns off the switch 121 in FIG. 12 and sends a signal to the moving means 123 to move the head unit 102 to the target track position.
[0082]
While the system controller 117 is turning off the switch 121 and moving the head unit 102, the state of the selector 206 (FIG. 13) of the wobble PLL circuit 108 is switched so that the output of the comparator 211 passes.
[0083]
By the above operation, before the seek operation is completed, control for matching the frequency of the wobble clock to the “target value” is started. As described with reference to FIGS. 10 and 11, the target value has a value corrected based on the ratio N / N2 between the actual rotation speed N of the disk motor and the target rotation speed N2.
[0084]
When the value calculated as the target value of the wobble clock frequency is sent to the comparator 211 by the system controller, the target value is compared with the frequency of the wobble clock that has passed through the frequency divider 205 and the period measuring device 208. Then, according to the comparison result, the frequency of the wobble clock is controlled so as to match the broken line 601 in FIG.
[0085]
Next, the configuration of the wobble detection unit 107 functioning as a clock synchronization signal reproduction unit will be described with reference to FIG. The wobble detection unit 107 includes a band-pass filter for extracting a wobble detection signal from a wobble reproduction signal, and a comparator for binarizing the wobble detection signal.
[0086]
The pass band width of the variable band pass filter is determined by the resistors 303, 304, 305, 306 and the capacitors 307, 308, 309, 310, 311, 312 shown in FIG.
[0087]
The switches 301 and 302 in FIG. 14 are switched by a signal from the system controller 117 shown in FIG. 12, thereby changing the pass band width of the variable band pass filter. The filter characteristic is switched so as to indicate any of three stages of pass bandwidths indicated by lines 401, 402, and 403 in FIG.
[0088]
In the present embodiment, the system controller 117 can send a signal to the wobble detection unit 107 to switch the characteristics of the band-pass filter. Specifically, the target value of the wobble clock frequency obtained from the target reproduction speed, the rotation speed N of the disk motor, and the target rotation speed N2 at the seek destination shows a filter characteristic such that the target value is included in the pass bandwidth. Then, a band switching signal is sent to the switches 301 and 302. In response to the band switching signal, the switches 301 and 302 operate to control the wobble detection unit 107 so as to exhibit appropriate filter characteristics from the three filter characteristics shown in FIG. 15, for example.
[0089]
As a result, a signal of a required frequency can be transmitted from the wobble detection unit 107 to the wobble PLL circuit 108 and the data PLL circuit 112 without passing a signal of an unnecessary frequency.
[0090]
By employing the above configuration, even when the reproduction speed is changed or CAV reproduction is performed, there is no problem that the frequency of the wobble signal included in the reproduction signal deviates from the pass band of the band-pass filter.
[0091]
It should be noted that the system controller 117 changes the state of the wobble PLL circuit 108 shown in FIG. 12 again at the time point t1 when the seek operation ends. That is, the system controller 117 switches the selector 206 (FIG. 13) in the wobble PLL circuit 108 so that the output of the comparator 210 passes, and turns on the switch 121 shown in FIG. As a result, the tracking control starts. Then, when the frequency of the wobble clock reaches a certain ratio with the wobble signal frequency, the selector 206 shown in FIG. 13 is switched, and the phase is switched to PLL phase control in which control is performed based on the phase of the wobble signal and the wobble clock. The operation of the PLL phase control is the same as the operation described with reference to FIG.
[0092]
The system controller 117 sends a signal to the wobble detection unit 107 until the rotation speed N of the disk motor becomes close to the target rotation speed N2, and determines the characteristics of the band-pass filter to the target reproduction speed and the rotation speed N of the disk motor. The switches 301 and 302 are appropriately switched so that the frequency of the wobble signal obtained from the target rotation speed N2 in the zone where the beam spot is located passes.
[0093]
By employing such a configuration, even when the response of the disk motor is slow, the wobble clock frequency has a value close to the frequency for reproducing the wobble signal (wobble reproduction frequency) at the end of the movement of the head unit 102. . As a result, the PLL phase control can be started immediately after the movement of the head unit 102 is completed, and the time required to start reading or recording data can be reduced.
[0094]
In the present embodiment, the wobble clock frequency is corrected based on the current motor speed N and the motor speed N2 at the target position. However, when the fluctuation of the motor rotation speed N is large, the rotation speed of the next rotation greatly differs from the current rotation speed. For this reason, even if the correction is performed, the error increases.
[0095]
In order to solve this, it is preferable to provide, for example, a rotation speed detector (not shown) for detecting the rotation speed of the optical disk. Then, it is preferable to control the variable oscillator 204 and set the wobble clock frequency in accordance with the actual rotation speed of the optical disk detected by the rotation speed detector and the target rotation speed in the zone to which the target track belongs.
[0096]
Specifically, the rotation speed N before one rotation _old And the next rotation speed is obtained from the current rotation speed N by linear interpolation, and the target of the read clock frequency having a constant ratio to the wobble clock frequency is obtained from the calculated next rotation speed and the destination rotation speed N2. The value is (2 × N−N _old It is preferable to correct the target frequency by multiplying the target frequency by N) / N2. By performing such a correction, the accuracy of the correction can be improved. This effect is particularly effective when the head unit is moved over a long distance. This is because when the head unit is moved over a long distance, the fluctuation of the motor rotation speed becomes large.
[0097]
In the present embodiment, wobble clock frequency correction is started simultaneously with the start of the seek operation, but the present invention is not limited to this. For example, in FIG. 11, as long as the wobble clock frequency can be made to match the value indicated by the broken line 601 before time t1, the correction start timing may be any time (for example, immediately before the seek operation ends).
[0098]
The optical disk device of the present embodiment has a sector interval measuring device 124 as shown in FIG. Hereinafter, the role of the sector interval measuring device 124 will be described.
[0099]
According to the conventional optical disk device, if the head unit 102 is largely displaced from the target track due to vibration or impact during the movement of the head unit 102, even if the tracking control is started by turning on the switch 121 shown in FIG. There is a possibility that the pass band of the band pass filter in unit 107 and the wobble reproduction frequency are shifted. In that case, the wobble signal cannot be detected, and the frequency of the wobble clock or the read clock cannot be controlled. If these clock frequencies cannot be set properly, the address of the destination track cannot be read.
[0100]
In order to solve such a problem, in the present embodiment, a sector interval measuring unit 124 is provided, and the system controller detects the reproduction time of the sector based on the sector interval measured by the sector interval measuring unit 124. Then, based on the detected reproduction time and the number of rotations of the motor, the zone where the convergence point of the light beam is located is determined.
[0101]
A specific configuration example of the sector interval measuring device 124 will be described with reference to FIG. The sector interval measuring device 124 includes a noise canceling device 901 and a period measuring device 902. The sector interval measuring unit 124 receives the address part detection signal output from the address part detecting unit 106, supplies the signal to the noise canceling unit 901, and determines the signal interval after passing through the noise canceling unit 901 by the period measuring unit 902. Measure. The noise canceller 901 cancels noise such that detection signals of the address units 1205 and 1206 are continuously detected from the address unit detection signal. Thus, the sector interval measuring device 124 can measure the reproduction time interval of the sector based on the address part detection signal.
[0102]
The frequency band control unit including the system controller 117 and the switches 301 and 302 (FIG. 14) in the wobble detection unit 107 selects an appropriate filter frequency characteristic based on the measured reproduction time interval. More specifically, the system controller 117 determines a zone in which the light beam is located based on the measured reproduction time interval of the sector and the number of rotations of the motor. Then, the characteristic of the band-pass filter is changed so that the pass band of the band-pass filter in the wobble detection unit 107 is suitable for extracting the wobble reproduction frequency in the zone where the light beam is located. Such a change in the filter characteristics is performed by appropriately switching the switches 301 and 302 shown in FIG. 14 similarly to the above-described method.
[0103]
By adopting such a configuration, even if the track to be sought is greatly different from the target track due to vibration, shock, or the like, a band-pass filter having appropriate characteristics can be set. It is possible to do.
[0104]
(Embodiment 2)
Next, a second embodiment of the optical disc device according to the present invention will be described. Since the basic configuration of the optical disk device of the present embodiment is the same as the basic configuration of the optical disk of the first embodiment, the present embodiment will be described mainly with reference to FIGS. .
[0105]
A feature of the present embodiment is that a rotation speed control unit that keeps the rotation speed of a disk motor (not shown) constant is provided. Thus, the optical disk device of the present embodiment can perform the CAV operation as needed.
[0106]
In the present embodiment, before the seek operation is started (when tracking control is performed), the selector 206 (FIG. 13) of the wobble PLL circuit 108 is switched so that the output of the phase comparator 201 passes. The clock is controlled so that its frequency has a fixed ratio to the wobble signal frequency. The generation of the wobble clock at this stage is the same as that in the conventional optical disk device.
[0107]
Next, as in the above-described embodiment, when the movement of the head unit 102 is started from this state, the system controller 117 turns off the switch 121 in FIG. 12 to release the tracking control. Then, by sending a signal to the moving means 123, the head unit 102 is moved to the target track position.
[0108]
While the system controller 117 is moving the head unit 102 by turning off the switch 121, the selector 206 (FIG. 12) of the wobble PLL circuit 108 is switched so that the output of the comparator 211 passes.
[0109]
In the present embodiment, the wobble clock frequency in the seek (or movement) destination zone is set as the “target value” input to the comparator 211 of the wobble PLL circuit during CAV reproduction in which the disk motor is reproduced at a constant rotation speed. . In this regard, the present embodiment is basically the same as that described for the first embodiment, but differs from the first embodiment in that a CAV operation is performed. In the case of the CAV operation, the wobble clock frequency in the seek destination zone is determined based on the disk rotation speed kept constant regardless of the seek destination zone and the position of the seek destination zone.
[0110]
Next, a description will be given of the frequency of the wobble clock with respect to the radial position of the disc when reproducing the optical disc by CAV with reference to FIG. In the case of CAV reproduction in which the disk motor is reproduced at a constant rotation speed, the frequency of the wobble clock changes depending on the position of the zone to be reproduced. For example, when the head unit 102 is moved from the position x1 to be played back on the optical disk to the position x2, the wobble clock frequency changes from f1 to f2.
[0111]
Therefore, the system controller 117 determines a target wobble clock frequency based on the seek (or movement) destination zone, and inputs the target wobble clock frequency to the comparator 211 of the wobble PLL circuit shown in FIG.
[0112]
FIG. 17 shows the tracking error signal and the wobble clock frequency when the tracking operation is changed from the tracking operation to the seek operation again in the present embodiment.
[0113]
In FIG. 17, “f1” indicates the wobble clock frequency corresponding to the position of the light beam spot before the start of the seek, and “f2” indicates the wobble clock frequency corresponding to the position of the light beam spot after the seek. In the example shown in FIG. 17, the position of the light beam spot moves from the inner circumference to the outer circumference of the disk due to the seek operation. Note that a broken line 801 indicates the wobble clock frequency at the seek destination position.
[0114]
According to the present embodiment, at the stage before the end of the seek operation, the wobble clock frequency of the seek destination is obtained, and the wobble clock having this value is generated. It can be close to the indicated value (wobble clock frequency in the seek destination zone).
[0115]
Further, the optical disk device of the present embodiment includes the wobble detection unit having the configuration shown in FIG. 14 similarly to the first embodiment. Therefore, when performing a seek operation, the system controller 117 sends a signal to the wobble detection unit 107. The pass band of the band-pass filter can be set to a band suitable for extracting the wobble reproduction frequency in the seek destination zone.
[0116]
The system controller 117 changes the state of the wobble PLL circuit 108 shown in FIG. 12 at a time point t1 when the movement of the head unit 102 ends. That is, the system controller 117 switches the selector 206 (FIG. 13) in the wobble PLL circuit 108 so that the output of the comparator 210 passes, and turns on the switch 121 shown in FIG. As a result, tracking control is started. Then, when the frequency of the wobble clock reaches a certain ratio with the wobble signal frequency, the selector 206 shown in FIG. 13 is switched, and the phase is switched to the PLL phase control in which the control is performed based on the phases of the wobble signal and the wobble clock.
[0117]
By adopting such a configuration, even if the wobble reproduction frequency differs depending on the seek destination zone, control is performed so as to be close to the wobble clock frequency (broken line 801) in the seek destination zone during the seek operation. In this way, after the head unit 102 moves, the frequency of the wobble clock is controlled to be close to the data reproduction frequency, and the band-pass filter for generating the wobble signal is also suitable for the wobble reproduction frequency in the seek destination zone. It is set to show the filter characteristics. As a result, it is possible to shift to the PLL phase control immediately after the end of the movement, so that it is possible to reduce the time required from the seek operation to the start of reading or recording of data.
[0118]
In the first and second embodiments described above, after the movement of the head unit 102 is completed, the selector 206 in the wobble PLL circuit shown in FIG. 13 is in a state of transmitting the output from the comparator 210 to the phase compensator 203. Is switched as follows. However, when the accuracy of the frequency control and the movement accuracy of the head unit 102 are high, the wobble clock frequency is controlled to a value substantially equal to the target frequency of the movement destination. May be switched so that is transmitted to the phase compensator 203. In this case, the control immediately shifts to the control based on the output of the phase comparator 201, so that the time required to start reading or recording data can be further reduced.
[0119]
In the second embodiment, the rotation speed of the disk motor may be changed for the purpose of changing the reproduction speed. In this case, as in the first embodiment, the characteristics of the band-pass filter may be changed until the rotation speed of the disk motor approaches the target rotation speed. Specifically, it is preferable that the switching is performed so as to pass a wobble signal having a frequency determined from the target reproduction speed, the rotation speed of the disk motor, and the target rotation speed in the zone where the light beam spot is located. In this way, since the proper characteristics of the band-pass filter can always be given to the wobble detecting unit 107, the data can be read or recorded stably.
[0120]
(Embodiment 3)
Next, a third embodiment of the optical disk device according to the present invention will be described with reference to FIG.
[0121]
The optical disk device of the present embodiment has a data PLL circuit 112 having the same configuration as a conventional data PLL circuit, as in the above-described embodiment. The optical disk device of the present embodiment is different from the other embodiments in that a wobble PLL is not required. In the present embodiment, the data PLL is controlled using the wobble signal.
[0122]
The configuration of the data PLL circuit in the present embodiment is as shown in FIG. Therefore, also in the present embodiment, during the tracking operation, the selector 1706 (FIG. 6) in the data PLL circuit is in a state where the output of the phase comparator 1701 passes. Therefore, the read clock is controlled so that its frequency has a fixed ratio to the frequency of the wobble signal.
[0123]
However, unlike the other embodiments, the optical disk device of the present embodiment does not generate the wobble clock frequency at the seek destination before the end of the seek operation.
[0124]
The gate signal generator 1013 shown in FIG. 18 outputs an address part gate signal indicating an address part to the selector 110 based on a command from the system controller 1017. This address portion is determined based on the output signal of the address portion detection unit 106.
[0125]
When reading data from the data section or recording data in the data section, the system controller 1017 sends a signal to the gate signal generation section 1013, and the gate signal generation section 1013 outputs a data section gate signal indicating the data section. I do.
[0126]
In this state, the system controller 1017 turns off the switch 121, sends a signal to the moving unit 123, drives the moving unit 123, and moves the head unit 102 to a target track position.
[0127]
The system controller 1017 sends a signal to the wobble detection unit 107, and sets the pass band of the band-pass filter to a band suitable for extracting the wobble reproduction frequency in the seek destination zone. Then, when the movement of the head unit 102 is completed, the switch 121 is turned on and the tracking control is started.
[0128]
By adopting such a configuration, even when the wobble reproduction frequency is different depending on the seek destination zone, the band-pass filter for generating the wobble signal after the movement of the head unit 102 is provided with the band pass filter in the seek destination zone. A filter suitable for the wobble reproduction frequency is set. As a result, data reproduction or recording can be started immediately after the movement of the head unit 102 is completed.
[0129]
According to each of the above embodiments, during the seek operation, the wobble PLL can be controlled so as to obtain the wobble clock frequency in the destination track (zone), and the characteristics of the band-pass filter can be switched. By changing the characteristics of the band-pass filter in accordance with the seek destination, the wobble PLL can be operated stably, and the time required to start writing or recording data after the end of the seek operation can be reduced. .
[0130]
In order to select an appropriate filter characteristic of the band-pass filter, it is important to determine a moving speed of the light beam spot on the optical disc (abbreviated as “linear velocity” in this specification). When performing the CAV operation, the above linear velocity can be determined based on the track (zone) where the light beam spot is located. On the other hand, when performing the ZCLV operation, it can be determined by the track (zone) where the light beam spot is located and the rotation speed of the disk motor.
[0131]
In addition, since the actual linear velocity can be known by measuring the above-described sector interval (address section interval), the actual position of the light beam spot at the time when the seek operation is completed is greatly deviated from the original target position. However, since the appropriate filter characteristics can be set, the wobble signal can be reproduced.
[0132]
In each of the above embodiments, the information area is concentrically divided into a plurality of zones, and in each of the plurality of zones, the outer track has a lower recording linear density, and the innermost track of each zone has a lower recording linear density. Although an optical disk on which information is recorded so that the linear density is substantially constant on the optical disk is used, the present invention is not limited to this. The wobble of the track on the used optical disk does not have to have a simple sinusoidal waveform, but may be formed from a combination of a plurality of types of wobble patterns. In other words, the optical disc device of the present invention is not limited to recording / reproducing on a DVD-RAM, but can be used for recording / reproducing on a Blu-ray disc. In a Blu-ray disc, at least a part of a wobble track records sub-information such as address information.
[0133]
【The invention's effect】
According to the optical disc apparatus of the present invention, before the seek operation is completed, the operation of generating the wobble clock frequency corresponding to the seek destination track is started. Therefore, the data can be reproduced immediately after the seek operation is completed.
[0134]
When a rotation speed detecting unit for detecting the rotation speed of the optical disk is provided, the rotation speed of the optical disk changes according to the position of the light beam spot on the optical disk as in the ZCLV operation. Based on this, the clock signal frequency corresponding to the seek destination track can be corrected, so that a clock signal with an appropriate frequency can be generated.
[0135]
In another aspect of the present invention, a reproduction signal of a clock synchronization mark is extracted using a band-pass filter having a variable frequency band. By changing the frequency band in accordance with the detected linear velocity, the reproduction signal of the clock synchronization mark can be appropriately extracted and output even at the seek destination.
[Brief description of the drawings]
FIG. 1A is a schematic plan view showing an optical disk, and FIG. 1B is a plan view schematically showing a configuration of a certain zone on the optical disk.
FIG. 2 is a diagram showing a configuration of a track of the optical disc shown in FIG.
FIG. 3 is a block diagram illustrating a configuration of a conventional optical disc device.
FIG. 4A is a diagram illustrating a track structure, and FIGS. 4B to 4F are diagrams illustrating waveforms of various signals.
FIG. 5 is a diagram showing a configuration of an address detection unit 106 in the optical disc device of FIG.
FIG. 6 is a diagram illustrating a configuration of a data PLL circuit 112 in the optical disc device of FIG. 3;
FIG. 7 is a diagram illustrating a configuration of a wobble detection unit 1307 in the optical disc device of FIG. 3;
8 is a diagram showing a configuration of a wobble PLL circuit 1308 in the optical disk device of FIG.
9 is a diagram showing a tracking error signal before and after a seek, a disk motor rotation speed, and a wobble clock during ZCLV reproduction in the optical disk device of FIG. 3;
FIG. 10 is a graph showing the reproduction position dependency of the motor rotation speed during ZCLV reproduction.
FIG. 11 is a diagram showing a tracking error signal before and after a seek during ZCLV reproduction, a disk motor rotation speed, and a wobble clock in the first embodiment of the optical disc apparatus of the present invention.
FIG. 12 is a block diagram showing a configuration of a first embodiment of the optical disc device according to the present invention.
13 is a diagram showing a configuration of a wobble PLL circuit 108 in the optical disc device of FIG.
14 is a diagram illustrating a configuration of a wobble detection unit 107 in the optical disc device of FIG.
FIG. 15 is a graph illustrating bandpass filter characteristics of the wobble detection unit 107 in FIG. 14;
FIG. 16 is a graph showing the reproduction position dependence of the wobble signal frequency during CAV reproduction.
FIG. 17 is a diagram showing a tracking error signal before and after a seek during CAV reproduction, a rotation speed of a disk motor, and a wobble clock in the second embodiment of the optical disk device of the present invention.
FIG. 18 is a block diagram showing a configuration of a third embodiment of the optical disc device according to the present invention.
FIG. 19 is a diagram showing a configuration of a sector reproduction time detection unit that can be suitably used in each embodiment of the present invention.
[Explanation of symbols]
101 Optical Disk
102 head unit
107 Wobble detector
108 Wobble PLL circuit
117 System Controller
124 sector interval measuring instrument

Claims (15)

An optical disc device which converges and irradiates a light beam onto an optical disc having a clock synchronization mark and a recordable data part on a track to read information recorded on the optical disc, or writes information to the optical disc,
A motor for rotating the optical disc;
A photoelectric converter that converts reflected light or transmitted light from the optical disc into an electric signal and outputs the electric signal,
A clock synchronization signal reproducing unit that extracts and outputs a reproduction signal of the clock synchronization mark from the electric signal output by the photoelectric converter,
A clock generator that generates a clock signal of a variable frequency;
A phase synchronization control unit that controls the clock generation unit so that the clock signal is phase-synchronized with the output of the clock synchronization signal reproduction unit;
A moving device that moves a spot position of the light beam on the optical disc toward a target track in the optical disc;
With
When performing a seek operation to move the spot position of the light beam on the optical disc toward a target track in the optical disc, determine a frequency expected in the target track, and output a clock signal of the frequency to the clock generator. An optical disk device for controlling the clock generation unit so as to output the clock signal from the optical disk; The period during which the clock signal of the expected frequency in the target track is output from the clock generator starts in accordance with the timing of the start of the movement of the spot position of the light beam for the seek operation. 2. The optical disk device according to claim 1, wherein the operation is terminated before the movement of the optical disk is terminated. The optical disc has an information area divided into a plurality of zones concentrically,
In each of the plurality of zones, information is recorded so that the recording linear density becomes lower toward the outer track, and the recording linear density of the innermost track of each zone becomes substantially constant on the optical disc. And
2. The optical disk device according to claim 1, wherein the clock synchronization mark and the recordable data portion are provided in each zone. 2. The optical disk device according to claim 1, wherein the track of the optical disk has a wobble structure that periodically shifts in a radial direction, and the wobble structure functions as the clock synchronization mark. The optical disc device according to claim 4, wherein the wobble structure of the track on the optical disc also functions as a portion for recording address information. A rotation speed detection unit for detecting a rotation speed of the optical disc,
In a case where the rotation speed of the optical disc is changed according to the spot position of the light beam on the optical disc, the frequency of the clock signal is changed according to the detected rotation speed of the optical disc and the target in the zone to which the target track belongs. 2. The optical disk device according to claim 1, wherein the clock generator is controlled to have a frequency determined according to a rotation speed. A rotation speed control unit for keeping the rotation speed of the optical disk substantially constant,
2. The optical disk device according to claim 1, wherein the clock generator is controlled so that the frequency of the clock signal becomes a target frequency in the target track. An optical disc device for reading information recorded on the optical disc by converging and irradiating a light beam onto an optical disc having a clock synchronization mark and a recordable data portion, or writing information on the optical disc,
A motor for rotating the optical disc;
A photoelectric converter that converts reflected light or transmitted light from the optical disc into an electric signal and outputs the electric signal,
A signal of a specific frequency band is extracted from the electric signal output by the photoelectric converter, and the frequency band is variable.
A clock synchronization signal reproducing unit that extracts and outputs a reproduction signal of the clock synchronization mark from an output of the band-pass filter,
A clock generator that generates a clock signal of a variable frequency;
A phase synchronization control unit that controls the clock generation unit so that the clock signal is phase-synchronized with the output of the clock synchronization signal reproduction unit;
A linear velocity detecting unit that detects a linear velocity of the optical disc;
Frequency band control means for controlling the frequency band to be extracted by the band-pass filter,
The optical disc device, wherein the frequency band control means controls a frequency band to be extracted by the band pass filter based on an output of the linear velocity detecting unit. An optical disc device for reading information recorded on the optical disc by converging and irradiating a light beam onto an optical disc having a clock synchronization mark and a recordable data portion, or writing information on the optical disc,
A motor for rotating the optical disc;
A photoelectric converter that converts reflected light or transmitted light from the optical disc into an electric signal and outputs the electric signal,
A signal of a specific frequency band is extracted from the electric signal output by the photoelectric converter, and the frequency band is variable.
A clock synchronization signal frequency detection unit that detects a reproduction signal frequency of the clock synchronization mark from an output of the bandpass filter,
A read clock generator for generating a variable frequency read clock signal;
A frequency control unit that controls the read clock generation unit so that the frequency of the read clock signal has a fixed ratio with the frequency of the output of the clock synchronization signal frequency detection unit;
A phase synchronization control unit that controls the read clock generation unit so that the read clock signal is phase-synchronized with the electric signal output by the photoelectric converter;
A linear velocity detecting unit that detects a linear velocity of the optical disc;
Frequency band control means for controlling the frequency band to be extracted by the band-pass filter,
The optical disc device, wherein the frequency band control means controls a frequency band to be extracted by the band pass filter based on an output of the linear velocity detecting unit. A moving device for moving the light beam toward a target track in the optical disc,
A rotation speed detection unit for detecting a rotation speed of the optical disc that is changed according to the position of the light beam,
10. The optical disk according to claim 8, wherein the linear velocity detector detects the linear velocity based on the detected rotational speed of the optical disk and a frequency determined according to a target rotational speed in a zone to which the target track belongs. apparatus. A moving device for moving the light beam toward a target track in the optical disc,
A rotation speed control unit for keeping the rotation speed of the optical disc substantially constant,
10. The optical disk device according to claim 8, wherein the linear velocity detector detects a linear velocity based on a zone to which the target track belongs. The optical disc has an information area divided into a plurality of zones concentrically,
In each of the plurality of zones, information is recorded so that the recording linear density becomes lower toward the outer track, and the recording linear density of the innermost track of each zone becomes substantially constant on the optical disc. And
The optical disk device according to claim 8, wherein the clock synchronization mark and the recordable data portion are provided in each zone. The track of the optical disc is provided with an address portion,
An address unit detection unit that detects the address unit based on the electric signal output by the photoelectric converter,
A sector reproduction time measurement unit that measures a time interval when a light beam passes through the sector based on an output of the address unit detection unit,
With
The optical disk device according to claim 11, wherein the linear velocity detector detects a linear velocity based on an output of the sector reproduction time measuring means. 10. The optical disk device according to claim 8, wherein the track of the optical disk has a wobble structure that periodically shifts in a radial direction, and the wobble structure functions as the clock synchronization mark. The optical disc device according to claim 14, wherein the wobble structure of the track on the optical disc also functions as a portion for recording address information.

Images